Techniques are disclosed for making hot melt thermoplastic adhesive foams in United States applications Ser. No. 710,377 and 710,378, filed Aug. 2, 1976, now U.S. Pat. Nos. 4,059,714 and 4,059,466, assigned to the assignee of this application. These patents are directed to methods of making and using hot melt foamed adhesives which offer significant improvements over conventional non-foamed adhesives. According to the techniques described in these applications, the gas is intimately mixed with a thermoplastic adhesive while the adhesive is in a molten state and then the mixture is pressurized to form a solution which, upon dispensing at a lower pressure, releases the gas and foamed adhesive results. The techniques described in these patents result in very useful foamed adhesives and bonding techniques. However, such techniques are not entirely satisfactory in producing hot melt thermoplastic adhesives on a continuous, uniform quality basis. Such techniques have also been found to be limited in their applicability to hot melt thermoplastic materials and further improvements are needed.